Divide mayo into 2 bowls; add horseradish to one and ketchup to the other; blend well.

Slice bread in thirds horizontally. Place top slice of bread, crust side down, in appropriate bowl or on a plate. Spread with mayo-horseradish. Cover with shrimp and scallops. Add next layer of bread. Spread with mayo-ketchup. Cover with salad. Add final bread slice bottom side up on top. Butter well. Arrange strips of cheese and rolled ham alternately in a design around to edges. Place a slice of tomato in the center. Decorate with slices of hard boiled egg, and anything you'd like to add (red pepper, olives, cucumber, lox, shrimp, etc.). Cover and refrigerate or serve immediately.

This Smorgastrata is a model. Build your own according to your likes and what you have on hand. There are no rules. It's not fancy. This is Regular! ;)